1. Field of the Invention
The present invention concerns the implementation of a semiconductor optical component and interfacing it to an external optical element. It is more specifically directed to solving a known problem which is to obtain two results simultaneously. A first result to be obtained is to "process" light efficiently in the optical component in question, the term "process" here referring to such actions as emitting, amplifying, detecting or modulating the light. Reference will often be made hereinafter, by way of non-limiting example only and with a view to facilitating an understanding of the present invention, to an optical component in which the light is processed in the form of a laser. The light to be processed is then in the form of a wave guided in the laser in a so-called narrow mode whose mode size may be limited by considerations concerning the required efficiency and the internal operation of the laser. The second result to be achieved is that the light processed in this way is supplied to said external optical element or can be received efficiently from said element in the form of a wide guided mode whose mode size is greater than that of said narrow mode. A wide mode of this kind typically has the advantage of enabling easier and more efficient coupling of this wave to an optical fiber which receives or supplies the light processed or to be processed.
2. Description of the Prior Art
A first known solution to this problem is described in "Tapered waveguide InGaAs/InGaAsp multiple quantum well lasers" by T. L. KOCH, U. KOREN, G EISENSTEIN, M. G. YOUNG, M. ORON, C. R. GILES and B. I. MILLER, IEEE Photonics technology letters, Vol. 2, No 2, February 1990, page 88.
This document describes a semiconductor laser emitting a wide guided mode. This laser is complex to implement.
A second known solution to this problem is described in "Efficient coupling of a semiconductor laser to an optical fiber by means of a tapered waveguide on silicon" by Y. SHANI, C. H. HENRY, R. C. KISTLER, K. J. ORLOWSKY and D. A. ACKERMAN, Appl. Phys. lett. 55, December 1989, page 2389.
This document describes a coupling device which receives a narrow mode at the output of a semiconductor laser and transmits a wide mode facilitating coupling to an optical fiber.
The insertion of a device of this kind complicates the implementation of an optical head which must couple the laser to the optical fiber in a limited space. It is also difficult to position the coupling device relative to the laser.
One object of the present invention is to propose a solution to this problem which is simple to implement, requires only a limited space and results in only low losses of light.